1. Field of the Invention
The present invention relates to a visible light (light that the human eye can see) control apparatus and a visible light control circuit that control blinking of visible light, a visible light communication apparatus that performs information communication using visible light that is controlled by the visible light control apparatus, a visible light control apparatus having mounted thereon the visible light control circuit, or controlled by the visible light control circuit, and a visible light control method for the visible light control apparatus.
2. Description of the Related Art
Conventionally, infrared rays, which are invisible to the human eye, are used when information communication is performed. The reasons for this are that infrared rays have higher transmission efficiency than visible light and visible light is likely to be visually annoying or obstructive to persons.
Visible light, however, allows a person to visually identify a visible light receivable region and thus is superior to infrared rays in terms of convenience, entertainment, etc., depending on the application. Visible light is a type of wave that is the same as radio waves and thus is, needless to say, capable of transmitting information.
Hence, for a technical document filed prior to the present invention, there is a document that discloses a location information communication apparatus which includes: a location data unit that generates location information; a modulation unit that modulates an electrical signal on a power line based on the location information from the location data unit; and an illumination unit that generates illumination light by the electrical signal modulated based on the location information, and which performs communication of the location information by utilizing optical wireless communication by the illumination light (visible light) (see patent document 1, for example).
In addition, there is a document that describes the possibility of visible light communication (see non-patent document 1, for example).
Visible light has important characteristics, i.e., high-speed blinking. By allowing the visible light to blink at a high speed that the human eye cannot perceive, various information can be transmitted. Therefore, by performing information communication using visible light, various problems associated with wireless communication and infrared-ray communication can be overcome, and ubiquitous (omnipresent) and ultrahigh-speed communication that does not adversely affects the human body or an electronic device can be performed.
[Patent Document 1] Japanese Patent Application Laid-Open No. 2005-218066
[Non-Patent Document 1] Masao Nakagawa, “Ubiquitous Visible Light Communications”, the Transactions of the Institute of Electronics, Information and Communication Engineers (IEICE), IEICE Transactions on Communications 2005, B Vol. J-88-B, No. 2, pp. 351-359